An anatomical view of a human stomach S and associated features is shown in FIG. 1A. The esophagus E delivers food from the mouth to the proximal portion of the stomach S. The z-line or gastro-esophageal junction Z is the irregularly-shaped border between the thin tissue of the esophagus and the thicker tissue of the stomach wall. The gastro-esophageal junction region G is the region encompassing the distal portion of the esophagus E, the z-line, and the proximal portion of the stomach S.
Stomach S includes a fundus F at its proximal end and an antrum A at its distal end. Antrum A feeds into the pylorus P which attaches to the duodenum D, the proximal region of the small intestine. Within the pylorus P is a sphincter that prevents backflow of food from the duodenum D into the stomach. The middle region of the small intestine, positioned distally of the duodenum D, is the jejunum J.
FIG. 1B illustrates the tissue layers forming the stomach wall. The outermost layer is the serosal layer or “serosa” S and the innermost layer, lining the stomach interior, is the mucosal layer or “mucosa” MUC. The submucosa SM and the multi-layer muscularis M lie between the mucosa and the serosa.
Prior art treatments for obesity range from diet and medication to highly invasive surgical procedures. Some of the more successful surgical procedures are the vertical banded gastroplexy or the proximal gastric pouch with a Roux-en-Y anastomosis. However, known complications are present with each of these procedures. More successful and less invasive options are desired.
A less invasive prior art treatment for obesity includes implantation of a gastric balloon delivered into the stomach via the esophagus. The balloon is an obstructive device—it prevents overeating by occupying volume within the stomach. Although implantation of a gastric balloon is less invasive than other surgical procedures, gastric balloons can migrate down the GI tract, causing obstruction and thus necessitating removal.